Abrasion resistant coatings

ABSTRACT

Pelletized thermoplastic polymers or resins containing (--CONH--) groups such as the nylons can readily be brominated or chlorinated in organic solvents to convert the (--NH--) units to (--NBr--) or (--NCl--) units and to form solutions of the N-brominated or N-chlorinated thermoplastic polymers or resins. These N-brominated or N-chlorinated thermoplastic polymer solutions can be coated on a cellular or solid rubbery hydrocarbon polymer substrate, such as an EPDM rubber in the form of a weatherstrip or glass run channel, dried and irradiated with ultraviolet light or heated at a temperature and for a period of time sufficient to reform the amide (--CONH--) groups and to provide the rubbery substrate with an adherent and abrasion resistant coating which also exhibits reduced ice adhesion and coefficient of friction.

This invention relates to abrasion resistant coatings and in particularto abrasion resistant coatings of thermoplastic polymers or resinshaving amide (--CONH--) groups on rubbery substrates.

Rubber weatherstrip materials used around doors and windows inautomobiles are subject to extensive wear. For example, abrasion of theautomotive weatherstrip occurs in various areas around an automobiledoor opening, for example in corner areas as the door is closed and inthe lower areas of the door opening as a result of contact with the feetof passengers entering or leaving the automobile. This abrasionultimately results in severe damage and failure of the weatherstrip.Automobile rubbery glass run channels, also, are subjected toconsiderable wear.

An object of this invention is to avoid the difficulties alluded toabove and to provide rubbery or rubber substrates with abrasionresistant coatings from thermoplastic polymers having amide (--CONH--)groups.

Another object of this invention is to provide a method for making acomposition useful for forming an abrasion resistant coating on rubberyhydrocarbon polymer substrates.

A further object of this invention is to provide a method for formingabrasion resistant coatings on rubbery substrates.

These and other objects and advantages of the present invention willbecome more apparent to those skilled in the art from the followingdetailed description, working examples and accompanying drawings inwhich

FIG. 1 is a vertical perspective view of an automobile weatherstrip;

FIG. 2 is a plan view of a reinforcing perforated metal strip for theweatherstrip;

FIG. 3 is a cross section of the weatherstrip;

FIG. 4 is a side elevation of the weatherstrip with a portion thereofbroken away to show that the weatherstrip includes the metal strip;

FIG. 5 is a vertical perspective view of an automobile glass run channeland

FIG. 6 is a cross section of the glass run channel showing its use.

SUMMARY OF THE INVENTION

It has been found that a solid, pelletized and thermoplastic polymer orresin having amide, (--CONH--), groups such as nylon 11 can bebrominated or chlorinated in aqueous suspension in the presence of anorganic solvent to form a solution in the solvent of a bromine orchlorine containing thermoplastic polymer wherein the (--NH--) unit hasbecome a (--NBr--) or (--NCl--) unit. A solution of this material whenapplied to a cured or vulcanized rubbery substrate, e.g., an EPDMrubber, dried to remove the solvent and then exposed to ultravioletradiation or heated at a temperature and for a period of time sufficientto remove the chlorine or bromine atoms and to reform the (--NH--) unitsto reproduce the amide (--CONH--) group yields an adherent and abrasionresistant polymer or resin coating on the rubber substrate. In additionto an improvement in abrasion resistance the coating providesimprovements in other properties such as ice adhesion and coefficient offriction.

In making a weatherstrip as depicted in FIGS. 1 to 4 of the drawings twovulcanizable EPDM rubber compounds are coextruded, one compound beinggenerally of U-shape and containing the perforated metal reinforcingsheet formed in the shape of a U and the other compound being hollow andgenerally round and containing a blowing agent. After leaving theextruder, the composite strip is passed through a molten salt bath toeffect vulcanization or curing as well as blowing and is then washed orotherwise treated to remove any salt on the surface. Other methods, ofcourse, can be used for vulcanization. After cleaning, drying andcooling the sponge or blown part of the weatherstrip is coated on itsouter surface with the composition of the present invention, dried andheated under ultraviolet lamps to form the adherent and abrasionresistance plastic coating of this invention on the surface of theresilient sponge part of the weatherstrip. The sponge part of theweatherstrip, of course, is the part subject to the abrasive actionduring the opening and closing of doors and hoods of automobiles andother vehicles. The sponge part of the coextrusion can be solid insteadof hollow, likewise, the part of the coextrusion subject to abrasion canbe a hollow, round and solid integral part, or it can be a round solidintegral part of the coextrusion.

In FIGS. 1 to 4 coating 1 of this invention is adherent to the surfaceof rubber foam part 2 integral with solid U-shaped surface of rubbermember 3 containing perforated U-shaped metal member 4. Rubber member 4also contains a number of rubber fingers 5 to grip flange 6 of the cardoor or hood.

In FIGS. 5 and 6 there is shown a glass run channel made of avulcanizable EPDM rubber which has been extruded, cured in a salt bath,cleaned, dried and cooled. The surfaces to be in contact with the glasshave been coated with the composition of the present invention, driedand heated under ultraviolet lamps to form an abrasion resistantcoating. Rubber extrusion 10 has coating 11 on several parts to be incontact with glass 12 such as the window glass in an automobile windowframe 13.

DISCUSSION OF DETAILS AND PREFERRED EMBODIMENTS

The (--CONH--) containing abrasion resistant thermoplastic polymer isselected from the group consisting of polyacrylamides, polyamide-imides,polysulfonamides, polyurethanes, polyureas, polyurethane-ureas andpolyamides and mixtures of the same. These polymers are well known asshown by the "Encyclopedia Of Polymer Science And Technology,"Interscience Publishers, a division of John Wiley & Sons, Inc., NewYork, Vol. 1 (1964), Vol. 10 (1969) and Vol. 11 (1969) and "Vinyl AndRelated Polymers," Schildknecht, John Wiley & Sons, Inc., New York,1952. Of these N-containing thermoplastic polymers it is preferred touse the polyamides such as the nylons.

Examples of the nylons are those having long chains with recurring(--CONH--) groups as an integral part of the polymer chain. They aremade by polyaddition of acrylamide, ring opening polymerization of,e.g., pyrrolidone, caprolactam and lauric lactam or by polycondensationof, e.g., aminononanoic acid, 11-aminoundecanoic acid, hexamethylenediamine with adipic or sebacic acid and p-phenylene diamine withterephthalic acid and the like and modifications of the same asillustrated by U.S. Pat. Nos. 4,414,362 and 4,448,956 and others.Mixtures of nylons can be used.

The thermoplastic (--CONH--) polymer to be chlorinated or brominated isgenerally used in pelletized form. If the thermoplastic is in massiveform as obtained, it may be reduced in size using granulators, dicers,die face cutters, strand pelletizers, underwater pelletizers and soforth. If necessary, the thermoplastic may first be cooled or frozen tofacilitate size reduction.

Various reagents and mixtures thereof can be used to brominate orchlorinate the thermoplastic (--CONH--) polymers including sodiumhypobromite, hypochlorous acid, salts of hypochlorous acid (aqueouscalcium hypochlorite or aqueous sodium hypochlorite (preferred)), alkylhypochlorites (t-butyl hypochlorite), elemental bromine or chlorine,dibromomonoxide and dichloromonoxide. Aqueous solutions of hypobromousacid or hypochlorous acid and the like are preferably used forbromination or chlorination. These solutions are most convenientlyobtained by addition of acids such as aqueous hydrobromic, hydrochloric(preferred), sulfuric or acetic acid to solutions of the sodium salts ofhypobromic or preferably hypochloric acid.

The halogenation reaction is carried out in the presence of an organicsolvent. This solvent has to be immiscible with water and inert underthe reaction conditions; it has to dissolve the N-halogenated polymerwith ease but not the original amide group containing polymer. Examplesof solvents are methylene chloride (preferred), carbon tetrachloride,chloroform, tetrachloroethane, trichloroethane, benzene and toluene.

A preferred procedure for the preparation of the N-halogenated materialused in the invention is to disperse pellets of the (--CONH--) polymerin a mixture of an aqueous solution of Na-hypochlorite (CHLOROX, 5.25%Na-hypochlorite) and the organic solvent (CH₂ Cl₂) and add concentratedhydrochloric acid in a nearly stoichometric amount based on theNa-hypochlorite. The mixture is slurried at room temperature (ca 25%) orbelow until the pellets dissolve. The organic layer containing thedesired product is separated and washed with water. The solutionobtained can be used in the coating process directly or afterappropriate dilution. Or, the solid product can be obtained by solventevaporation for easier shipment.

The brominated or chlorinated thermoplastic (--CONH--) polymer ormixture thereof is used in an amount of from about 1 to 50%, preferablyabout 2 to 4%, by weight solids in a solvent such as one or more of theabove chlorinated hydrocarbons like methylene chloride for use as acoating material. A uniform application of the coating can be obtainedwith a low solids solution. Fillers such as the finely divided silicas,also, can be included in the coating formulation to reduce gloss, lowercost and improve performance. It has been found that the addition of asmall amount of finely divided silica actually improved abrasionresistance. Other pigments and additives such as carbon black can beadded to the coating composition.

The rubber substrate such as a weatherstrip or glass run channel and soforth can be a rubbery hydrocarbon polymer selected from the groupconsisting of natural rubber; high cis-polyisoprene; emulsionstyrene-butadiene copolymers; solution styrene-butadiene copolymerswhich may be low vinyl, medium vinyl, high vinyl or high trans randomSBR's; butadiene- or isoprene-styrene star copolymers; block(thermoplastic elastomer) styrene-butadiene-styrene orstyrene-isoprene-styrene copolymers; butyl rubber; high molecular weightpolyisobutylenes; EPDMs (ethylene-propylene-nonconjugated dienecopolymers) (preferred) and so forth and mixtures of the same. Thesepolymers are well-known. These rubbery polymers are mixed with the usualcuring and compounding agents for the particular polymers being used andcured or vulcanized. Examples of some agents are reinforcing blacks;silica; clay; TiO₂ ; stearic acid; zinc oxide; sulfur; dibenzo GMF withred lead or with peroxides; peroxides; sulfur furnishing materials;retarders; accelerators; antioxidants; blowing agents likeazodicarbonamide, p,p'-oxybis(benzenesulfonyl hydrazide) anddinitrosopentamethylene tetramine (preferred) and so forth. The rubbermay be solid or blown (cellular--open or closed cell) depending on theultimate use.

Ethylene-propylene-nonconjugated diene rubbery terpolymers (EPDMs) aremade by the copolymerization of ethylene, propylene and a non-conjugateddiene such as 1,4-hexadiene (preferred), ethylidene norbornene ordicyclopentadiene. They may be crystalline or non-crystalline and may berandom, block or sequence terpolymers. Their relative unsaturation canvary from about 0.7 to 7.5. The mole % of ethylene can vary from about50 to 85 and the raw (uncured and uncompounded) Mooney viscosity (ML 1+8at 250° F.) can vary from about 14 to 84. Rubbery or elastomeric EPDMterpolymers, methods for making them and methods for curing them areshown by "Rubber Chemistry And Technology," Volume 45, No. 1, March,1972, Division of Rubber Chemistry, Inc., American Chemical Society,pages 709 to 881; "Rubber Technology," 2nd Ed., Morton, Van NostrandReinhold Company, New York, 1973, Chapter 9; "Polymer Chemistry ofSynthetic Elastomers," Part II, High Polymers Series, Vol 23, John Wiley& Sons Inc., New York, 1969, Chapter 7; "Encyclopedia Of Polymer Scienceand Technology," Interscience Publishers a division of John Wiley &Sons, Inc. New York, Vol. 6 (1967) pages 367-8 and Vol. 5 (1966) page414 and "Synthetic Rubber Manual," International Institute of SyntheticRubber Producers, Inc., 8th Ed., 1980.

The coating solution can be applied to the rubbery substrate such as aweatherstrip or glass run channel using any conventional coatingtechnique (brush, print roller, dip or spray). The coating may beapplied to one side or to all sides. Generally, it is applied only tothe side requiring improved abrasion resistance. After application tothe weatherstrip the solvent is evaporated leaving a film ofN-brominated or N-chlorinated thermoplastic on the surface. Byapplication of heat or UV irradiation the bromine or the cnlorine isreleased from the nitrogen atoms and the (--NH--) unit and carbonyl bandare reformed to provide the recurring amide groups. Some cross-linkingmay take place during this process. These treatments result in formationof strong, abrasion resistant and non-tacky coatings. Good adhesion tothe rubber results since the N-brominated or N-chlorinated thermoplasticis a strong oxidizing agent which can react with the rubbery substrategenerating polar groups on its surface, and/or giving primary bondingbetween the rubber and the coating at the interface. The preferredmethod is to use UV treatment which is much faster and gives aconsistent product. The irradiation with ultraviolet light should bedone at wavelengths of not over about 375 nm, preferably not over about350 nm. Other treatments may be effective in converting the N-brominatedor N-chlorinated thermoplastic back to the amide form (e.g., treatmentwith steam, aqueous base and/or a solution of a reducing agent such assodium bisulfite or sulfite). The heat treatment or other treatment isconducted for a period of time and at a temperature sufficient forcomplete conversion of the N-brominated or N-chlorinated units of thethermoplastic back to the amide NH form.

Although the working examples are directed mostly to improvement of theabrasion resistance of automotive weatherstrip and glass run channel,the coating material may be useful to improve the abrasion resistance ofother substrates such as windshield wipers, vinyl films, upholstery,luggage and so forth.

The following examples will serve to illustrate the present inventionwith more particularity to those skilled in the art. In the followingexamples the parts are parts by weight unless otherwise indicated.

EXAMPLE 1 Preparation of N-Chlorinated Nylon 11

Into a pint bottle were placed CHLOROX (118 grams, 5.25% aqueous sodiumhypochlorite) and methylene chloride (100 ml). Concentrated hydrochloricacid (8.0 grams) was slowly added with stirring. The contents of thebottle were allowed to cool to room temperature (ca 25° C.) and nylon 11pellets (5.0 grams, Rilsan Corporation) were added. This mixture wasstirred for 2 hours at room temperature. The contents of the bottle werefiltered to remove any unreacted nylon 11 and the methylene chloridelayer of the two-phase mixture was separated from the aqueous layerusing a separating funnel and carefully washed with water. The solidN-chlorinated nylon 11 was recovered by precipitation by pouring themethylene chloride into swirling hexane. An 87% yield of N-chlorinatednylon 11 was obtained (M.P. 90° C). It, also, could be recovered byevaporation of the methylene chloride. Infrared spectra of a sample ofthe product showed the absence of the (--NH--) absorbance at 3150 cm⁻¹and a shift in the carbonyl band (from 1640 cm⁻¹ for (--CONH--) to 1665cm⁻¹ for the N-chlorinated polymer), indicating complete formation ofN-chlorinated nylon 11. A 3% solution of the product in methylenechloride was prepared for coating. Nylon 11 is a type of nylon derivedfrom 11-aminoundecanoic acid. Presumably N-chlorination takes place onthe surface of the nylon pellet. The chlorinated nylon dissolves readilyin the methylene chloride phase exposing fresh surfaces for furtherchlorination. The N-chlorinated nylon 11 is readily soluble in methylenechloride and the resulting solution can be applied directly to an EPDMweatherstrip. Unmodified nylon 11, on the other hand, is only soluble insolvents such as formic acid and meta-cresol which are not suitable forcoating applications.

EXAMPLE 2 Abrasion Resistance of Coated Weatherstrip (Untreated Coating)

A cured EPDM automotive sponge weatherstrip (automotive N-body type) wascoated with a thin uniform film (a few mils thick) of the N-chlorinatednylon 11 solution prepared according to Example 1, above. A brush wasused to apply the coating. The solvent was evaporated and theweatherstrip was tested for abrasion resistance on a Wyzenbeek AbrasionTester. The abrasion tester was set for a 3 lbs. load with 5 lbs.tension on the specimen. The abrasion resistance was tested against asteel panel coated with automotive paint. After 20 cycles at roomtemperature, the weatherstrip had completely failed (the specimen brokeand a large amount of rubber had transferred to the painted metalpanel).

EXAMPLE 3 Abrasion Resistance of Coated Weatherstrip (Heat TreatedCoating)

A cured EPDM sponge weatherstrip was coated with the N-chlorinated nylonsolution and dried as in Example 2, above. The coated weatherstrip washeated for 1 hour at 100° C. Infrared spectra of the coated surfaceindicated complete conversion of the N-chlorinated nylon to the amide(--NH--) form and a return of the carbonyl band to 1640 cm⁻¹. The coatedweatherstrip, after waiting a few hours to insure that all of the HClhad escaped, was tested for abrasion resistance as in Example 2. After41,000 cycles, the sample was completely intact with no transfer ofrubber to the painted metal panel.

EXAMPLE 4 Abrasion Resistance of Coated Weatherstrip (UV TreatedCoating)

A cured EPDM sponge weatherstrip was coated with the N-chlorinatednylon-11 solution and dried as in Example 2. The coated weatherstrip wasirradiated with three UV lamps (200 watts/inch output each) for 2.5seconds. Infrared spectra indicated complete conversion of the coatingback to the amide (--NH--) form and a return of the carbonyl band. Thisweatherstrip then was tested for abrasion resistance as in Example 2,above. After 80,000 cycles, the sample was completely intact with notransfer of rubber to the painted panel.

EXAMPLE 5 Abrasion Resistance of Uncoated Weatherstrip

Uncoated, cured EPDM weatherstrip was tested for abrasion resistance asin Example 2, above. After 20 cycles, the weatherstrip had broken with alarge amount of rubber transferred to the painted metal panel.

EXAMPLE 6

A cured EPDM automotive weatherstrip sponge (automotive N-Body type) wascoated with a thin film of chlorinated nylon 11 solution prepared as inExample 1, above. A brush was used to apply the coating which was thendried. Then, the applied coating was cured by treatment with UV as inExample 4, above. Wyzenbeek abrasion resistance, ice adhesion andcoefficient of friction were determined for the coated weatherstrip andcompared with an uncoated weatherstrip. Data were obtained both beforeand after weathering for 200 hours in a Weather-Ometer. A non-coatedcontrol was used for comparison. A significant improvement in all threeproperties resulted from using the chlorinated, UV treated nylon 11coating. The data obtained are shown in Table 1, below:

                                      TABLE 1    __________________________________________________________________________               Wyzenbeek Abrasion                             Ice Adhesion               (Cycles)      (Newtons)** Coefficient of Friction**               Non-          Non-        Non-    Weatherstrip               Weathered                      Weathered                             Weathered                                   Weathered                                         Weathered                                               Weathered    __________________________________________________________________________    Non-Coated ≦20                      ≦20                             22    33    1.7   1.2    Coated with               >>125,000*                      >>110,000*                             8.5   19.3  0.5   0.45    Chlorinated    UV Treated Nylon 11    __________________________________________________________________________     *the test was terminated at the indicated cycle times.     **best results are indicated by the lowest figures.

EXAMPLE 7

A solid (non-cellular) cured EPDM stock used for automotive glass runwindow channel was coated with a chlorinated nylon 11 solution and UVtreated using materials and procedures described in Example 6, above.The abrasion resistance of the flat stock was tested using a scuffresistance tester equipped with a ground-glass abrasion tool. The coatedand treated flat stock passed 810 cycles compared to 1 cycle for anuncoated flat stock.

EXAMPLE 8 N-chlorinated Nylon 6

Pellets of Nylon 6 (10 gms), CHLOROX (250 gms, 5.25% aqueous sodiumhypochlorite), methylene chloride (250 ml) and concentrated aqueous HCl(20 gms) were placed in a pint bottle. The contents of the bottle werestirred for 71/2 hours at 5° C. The original nylon 6 pellets haddissolved after this period of time. The methylene chloride layer wasseparated from the aqueous layer using a separatory funnel and washedtwice with water. After evaporation of the methylene chloride, anamorphous solid product remained (11.79 gms). The infrared spectra of asample of the product showed the absence of the (--NH--) absorbance at3150 cm⁻¹ and a shift in the carbonyl band (from 1640 to 1665 cm⁻¹),indicating complete formation of N-chlorinated nylon 6. Nylon 6 is atype of nylon made by ring opening polymerization of epsiloncaprolactam.

EXAMPLE 9 N-chlorinated Nylon 6,6

The same procedure used for chlorinating nylon in Example 8, above, wasfollowed except that 10 gms of nylon 6,6 pellets were stirred with 250gms CHLOROX, 250 ml of methylene chloride and 20 gms of concentratedaqueous HCl. A solid product, a powder (11.15 gms) was obtained whichwas soluble in methylene chloride. Infrared spectra of a sample of theproduct indicated complete formation of N-chlorinated nylon 6,6. Nylon6,6 is a type of nylon made by condensing hexamethylene diamine withadipic acid.

EXAMPLE 10 N-chlorinated Nylon 12

The same procedure as used for chlorinating nylon 6 in Example 8, above,was followed except that 10 gms of nylon 12 pellets were stirred with250 gms CHLOROX, 250 ml of methylene chloride and 20 gms of concentratedaqueous HCl. An amorphous solid product was recovered (11.21 gms) whichwas soluble in methylene chloride. Infrared spectra of a sample of theproduct showed complete formation of N-chlorinated nylon 12. Nylon 12 isa type of nylon made by the polymerization of lauryl lactam (dodecanoiclactam) having 11 methylene groups between the linking (--CONH--) groupsin the polymer chain.

EXAMPLE 11

Cured EPDM automotive weatherstrip sponges (automotive N-Body type) werecoated, respectively, with the N-chlorinated nylon 6, nylon 6,6 andnylon 12 (Examples 8, 9 and 10 above). Coatings were prepared and curedby UV to the amide (--NH--) form as described in Example 4, supra.Wyzenbeek abrasion resistance was determined for the coated samples andcompared with an uncoated weatherstrip sponge as shown in Table 2,below:

                  TABLE 2    ______________________________________    Coating          Wyzenbeek Abrasion Cycles    ______________________________________    N--Chlorinated nylon 6,6                     2,640    N--Chlorinated nylon 6                     3,520    N--Chlorinated nylon 12                     1,760    Uncoated           20    ______________________________________

EXAMPLE 12

Nylon 11 pellets were chlorinated on the amide nitrogen usinghypochlorous acid according to the method of Example 1, supra. Afterchlorination, the product (N-chlorinated nylon) was readily soluble insolvents such as methylene chloride whereas the starting material nylon11 was insoluble. Cured EPDM cellular weatherstrip was coated with amethylene chloride solution (4%) of the N-chlorinated nylon, and themethylene chloride as well as water were evaporated completely. After UVtreatment (≲350 nm, ˜8 seconds), the nitrogen-bonded chlorine wasreleased and the amide (--NH--) form was restored (FT--IR--ATR) to givea smooth and non-sticky layer. The coating layer released trace amountsof HCl gas continuously over ˜1/2 day after UV irradiation. After theHCl release ceased, a coated weatherstrip with good properties wasobtained. Wyzenbeek abrasion-resistance of the weatherstrip wasincreased to more than 134,000 cycles for the coated weatherstripcompared to ˜20 cycles for an uncoated weatherstrip. Ice adhesionproperties were equivalent to a siloxane coated weatherstrip, andcoefficient of friction was similar to that of other coated materials.The EPDM used to make the cellular weatherstrips contained about 72parts ethylene and had very high unsaturation whereas the EPDM used tomake the stock of Example 7 contained about 50 parts of ethylene and hadvery high unsaturation.

The EPDM weatherstrip, solid or cellular, were made from sulfur curedand carbon black reinforced extruded rubbery copolymers. The cellular orsponge weatherstrips were blown with dinitrosopentamethylene tetramine.

nm: Nanometer (millimicron)

FT-IR-ATR: Fourier Transform--Infrared--Attenuated Total Reflectance

We claim:
 1. The method which comprises coating the surface of acellular or solid cured rubbery hydrocarbon polymer with a solution inan organic solvent of a chlorinated or brominated thermoplastic polymeror resin orginally having amide, (--CONH--), groups in which the(--NH--) units have been changed to (--NBr--) or (--NCl--) units, dryingand irradiating with ultraviolet light or heating the coated rubberypolymer for a period of time and at a temperature sufficient to convertthe (--NBr--) or (--NCl--) units to (--NH--) units to form the originalamide, (--CONH--), groups of the thermoplastic polymer and to form anadherent and abrasion resistant coating on the rubbery polymer.
 2. Themethod according to claim 1 where said thermoplastic polymer or resin isselected from the group consisting of polyacrylamides, polyamide-imides,polysulfonamides, polyurethanes, polyureas, polyurethane-ureas andpolyamides and mixtures of the same.
 3. The method according to claim 2where said rubbery hydrocarbon polymer is a cellularethylene-propylene-non-conjugated diene terpolymer.
 4. The methodaccording to claim 3 where said thermoplastic polymer or resin is apolyamide.
 5. The method according to claim 4 where said polyamide is anylon.
 6. The method according to claim 5 where said nylon is a nylonderived from 11-aminoundecanoic acid.